Skelp heating furnace



` Sept. '11), 1940. B. BANNISTER sxELP HEATING FURNAcE Filed Aug. l5. 1939 Patented Sept. 10, 1940 UNITED STATES SKELP HEATING FURNACE Bryant Bannister, Mount Lebanon, Pa., assigner to National Tube Company, a corporation of New Jersey Application August 15, 1939, Serial No. 290,281

, 1 Claim.

'I'his invention relates to a skelp heating furnace and more particularly to one which -is adapted for use in the production of continuous tubing 'from an endless length of at skelp which con- 5 tinuously travels through a furnace, the skelp being formed into a tube and its edges welded together by bending and Welding rolls or other instrumentalities located at the delivery end of the furnace, from which the skelp is delivered at a welding heat.

Ordinarily, the furnace is elongated in order to permit the heating of a considerable length of sk elp; and the bending and welding rolls operate to pull the skelp through the furnace. At the l5 entry en d of the furnace, the flat skelp is received for use in rolled form, and in order to deliver the skelp to the furnace in a continuous manner, it is necessary to weld the rear end of one roll of skelp to the front end of a fresh roll of skelp.

According to a prevalent mode of operation, the skelp is fed from one roll into the entry end of the furnace, and workmen unreel a length of skelp from said roll and weld the rear or trailing end thereof to the front or leading end of a fresh roll of skelp, the length of skelp uncoiled fromv the first roll in the meantime continuing to feed into the furnace. The fresh roll is then placed in the same position as the original roll.` Subsequently, by repeating the same operation, the rear or trailing end of the skelp from the second roll is welded to the front or leading end of the skelp on the third roll.

Due to the drag of the large loop formed by the rear or trailing end of the skelp going through the furnace, which is necessary when operating at high speeds, it was, prior to the invention of my copending application, Serial No. 278,558, led June l0, 1939, and entitled skelp feeding apparatus, impossible so far as I am aware to operate at speeds higher than approximately 350 feet per minute on small sized skelp, such as, for example, one-half inch. This was for the reason that the drag of the large loop caused the skelp to pull apart while in the furnace.

According to the invention of said copending application, there is provided a skelp` feeding device disposed between the welding -device and the entry end of the furnace, together with means permitting the formation of loops of skelp on either side of said rst-named device.

It is among the objects of the present invention to overcome the feeding defects referred to hereinbefore while at the same time providing for more efficient heating of the skelp. These desiderata result in an increased production of heated skelp, coupled with less fuel consumption and, according to the design which will be described hereinafter, is accomplished with lower initial or building costs.

The foregoing and other objects will be ap- 5 parent after referring to the drawing, in which:

Figure 1 is an elevation of a skelp feeding and heating apparatus embodyingthe furnace of the present invention, the latter of which is shown in section; l0

Figure 2 is an enlarged sectional side elevation of the furnace of Figure 1; and

Figure 3 is an enlarged sectional view on the line III-III of Figure 2.

Referring more particularly to the drawing, the 15 numeral 2 designatesa continuous heating furnace which is provided with an upper longitudinal preheating chamber 3 and a lower and parallel heating chamber 4. Referring more particularly to Figure 1, it will be noted that the skelp 20 S enters the preheating chamber 3 at the righthand end thereof, progresses the length of the preheating chamber 3, enters the heating chamber 4 at the left-hand end thereof and exits from the right-hand end of the heating chamber 25 4. The strip S enters'the preheating chamber 3 from the Welder and looping table and leaves the heating chamber 4 for the Welding and forming mill, all of which instrumentalities will be referred to more specifically hereinafter. 30

Referring to Figure 2, it will be noted that the heating furnace 2 provides restricted passages 5 between the upper preheating chamber 3 and the lower heating chamber 4, and suitable burner devices 6 are disposed along the. heating chamber 35 4 at desired intervals. According to this construction, Wherein the preheating chamber 3 is above the heating chamber 4, the exhaust gases from the latter are exhausted into the former and thence to recuperators through passages 9. 40

It will be noted that at suitable intervals along the bottom of the preheating chamber 3, and'also along the bottom of the heating chamber 4, there is disposed a series of refractory skids I0, which are adapted to support the skelp S. 45

At the left-hand end of the heating furnace 2 and disposed intermediately of the preheating chamberv 3 of the heating chamber 4, there is a pair of suitably driven pinch rolls I2, whose axes occupy a common horizontal plane. These driv- 50 en pinch' rolls I2 drag the strip of skelp S through thgpreheating chamber 3 and direct it into the heating chamber 4 from which it is drawn by the Welding and forming mill. According to this construction, the pinch rolls l2 reduce the amount of drag tension which would be required of an elongated heating furnace of the conventional variety.

Disposed `somewhat adjacent the entry (or right-hand) end of the preheating chamber 3, there is suitably mounted a pair of rolls I1 and I9, respectively, each of which carries a. roll of skelp. Included in the line of pass provided for the rolls of skelp I'I and I9, there is disposed a Welding machine 20, While immediately adjacent the Welding machine 20, is a pair of suitable driven pinch rolls 22 which are adapted to draw the skelp forwardly and permit the same to occupy a loop as at X, prior to the passage of the skelp into the heating furnace 2. At the exit (or right-hand) end of the heating chamber v4, there is disposed a tube forming machine 23, which comprises suitable instrumentalities such as bending and Welding rolls, and possibly also seizing rolls (none of which is shown).

While I have shown and described one specific embodiment of the present invention, it Will be seen that I do not Wish to be limited exactly thereto, since various modications may be made without departing from the scope of the invention, as defined by the following claim.

I claim:

A skelp heating furnace comprising, in combination, a chamber extending longitudinally of said furnace, a chamber disposed beneath and parallel to said first-named chamber, means for heating said second-named chamber, means for permitting the exhaust of the heating gases from said second-named chamber into said rst-named chamber, pinch rolls adjacent said furnace for pulling skelp through said rst-named chamber, said pinch rolls being constructed and arranged to reverse the direction of travel of said skelp and direct the same' into said second-named chamber, and refractory skids in both of said chambers for supporting the skelp;

BRYANT BANNISTER. 

